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 * and Distribution License("CDDL") (collectively, the "License").  You
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 * obtain a copy of the License at
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package com.sun.mail.smtp;

import java.io.*;
import com.sun.mail.util.CRLFOutputStream;

/**
 * In addition to converting lines into the canonical format,
 * i.e., terminating lines with the CRLF sequence, escapes the "."
 * by adding another "." to any "." that appears in the beginning
 * of a line. See RFC821 section 4.5.2.
 * 
 * @author Max Spivak
 * @see CRLFOutputStream
 */
public class SMTPOutputStream extends CRLFOutputStream {
	public SMTPOutputStream(OutputStream os) {
		super(os);
	}

	public void write(int b) throws IOException {
		// if that last character was a newline, and the current
		// character is ".", we always write out an extra ".".
		if ((lastb == '\n' || lastb == '\r' || lastb == -1) && b == '.') {
			out.write('.');
		}

		super.write(b);
	}

	/*
	 * This method has been added to improve performance.
	 */
	public void write(byte b[], int off, int len) throws IOException {
		int lastc = (lastb == -1) ? '\n' : lastb;
		int start = off;

		len += off;
		for (int i = off; i < len; i++) {
			if ((lastc == '\n' || lastc == '\r') && b[i] == '.') {
				super.write(b, start, i - start);
				out.write('.');
				start = i;
			}
			lastc = b[i];
		}
		if ((len - start) > 0)
			super.write(b, start, len - start);
	}

	/**
	 * Override flush method in FilterOutputStream.
	 * 
	 * The MimeMessage writeTo method flushes its buffer at the end,
	 * but we don't want to flush data out to the socket until we've
	 * also written the terminating "\r\n.\r\n".
	 * 
	 * We buffer nothing so there's nothing to flush. We depend
	 * on the fact that CRLFOutputStream also buffers nothing.
	 * SMTPTransport will manually flush the socket before reading
	 * the response.
	 */
	public void flush() {
		// do nothing
	}

	/**
	 * Ensure we're at the beginning of a line.
	 * Write CRLF if not.
	 */
	public void ensureAtBOL() throws IOException {
		if (!atBOL)
			super.writeln();
	}
}
